1. Field of the Invention
The present invention relates to an image recording member and a process for electrically recording an image by the application of electric current thereto.
2. Description of the Prior Art
Recording electrical signals as images has been increasing year by year with development of facsimile printers and recorders. Heretofore, there have been used electrical discharge recording paper and electrolyte recording paper, but they are not satisfactory because of bad odor and dust caused by recording procedure and poor image quality. In view of such unsatisfactory performance of the conventional recording papers, there have been recently proposed or put into practice some processes for electrically recording images by the application of electric current to recording papers as disclosed in Japanese Pat. Publication Nos. 22341/1963 and 101935/1973, that is, a recording paper having a layer of a metal compound such as zinc oxide and the like dispersed in a matrix having electric conductivity lower than that of the metal compound or a recording paper having a photoconductive material layer containing dispersedly a color forming agent capable of forming color by oxidation or reduction or energy change caused by electric current. The processes can produce images in an apparently dry procedure.
These electrical image recording papers do not give rise to bad odor and dust and can be easily handled due to their dry systems. These electrical image recording papers have fairly improved characteristics as compared with the prior art electrical discharge recording papers and electrolyte recording papers, but still have some disadvantage such as relatively low sharpness and low contrast probably due to spark at the time of recording, and therefore, the resulting image quality is almost similar to that obtained by the electrical discharge recording paper.
There has been proposed an improved electrical recording paper to give a better image quality (Japanese Patent Application No. 34332/1973). Since said electrical recording paper has a recording layer comprising a compound containing zeolitic water as a conductive component in place of the semiconductive material, no spark is caused between the stylus and the recording layer when recording is effected by applying electric current. Thus, neither electric discharging smell nor gas is generated and moreover, the resulting images are of high sharpness and high resolution. In general, when semiconductive materials are subjected to doping or reducing treatment to impart conductivity thereto, the semiconductive materials are apt to be colored, but compounds containing zeolitic water are highly conductive as well as white.
However, the electrical recording paper has a drawback that when the recording is effected by direct current (DC), recovering the return current from the surface of the recording layer by way of the recording layer is more difficult than in case of recording papers containing a semiconductive material as a conductive component. In other words, when the return current is recovered by bringing a return electrode material into contact with the surface of the recording layer, the recording layer is sometimes burnt and the metal thin layer directly beneath the return electrode is melted or vaporized.